CN107917748A - High-precision electronic scale - Google Patents
High-precision electronic scale Download PDFInfo
- Publication number
- CN107917748A CN107917748A CN201711193314.8A CN201711193314A CN107917748A CN 107917748 A CN107917748 A CN 107917748A CN 201711193314 A CN201711193314 A CN 201711193314A CN 107917748 A CN107917748 A CN 107917748A
- Authority
- CN
- China
- Prior art keywords
- circuit
- control circuit
- electronic scale
- precision electronic
- signal acquisition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
- G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
- G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
- G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
- G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
- G01G3/142—Circuits specially adapted therefor
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
Abstract
A kind of high-precision electronic scale, belongs to meausring apparatus field, it is characterised in that：Including front end signal Acquisition Circuit, amplifying circuit, power supply, D/A converting circuit, control circuit, display terminal and button；The front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit, control circuit are sequentially connected electrically；The control circuit is connected with display terminal；The button is connected with control circuit；The power supply is connected with front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit and control circuit respectively.The signal of collection is handled to be amplified signal by signal conditioning circuit and changed with A/D, it is subject to data processing with reference to STM32 singlechip controllers, and realized and inputted by outer keyboard circuit, show that low with amount of money cost, portable, intelligence of weighing is satisfied with daily demand by FTF display screens, small-sized smart scale market is worth with popularity.
Description
Technical field
The invention belongs to meausring apparatus field, more particularly to a kind of high-precision electronic scale.
Background technology
Weighing device becomes a part indispensable in life, is produced to heavy industry greatly, as low as street hawker.At present
Electronic scale of the electronic scale market generally existing based on 89C51 family chip developments, electronic scale signal condition circuit system it is more so that
Based on the processing of IC chip HX710A types single-chip, change conventional multicomponent device with internal analogue circuit integrated chip
Single convenient structuring is realized in accumulation welding.
The content of the invention
A kind of the present invention is intended to provide portable, inexpensive high-precision electronic scale device.
High-precision electronic scale of the present invention, including front end signal Acquisition Circuit, amplifying circuit, power supply, digital-to-analogue conversion
Circuit, control circuit, display terminal and button；The front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit, control
Circuit is sequentially connected electrically；The control circuit is connected with display terminal；The button is connected with control circuit；The power supply
It is connected respectively with front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit and control circuit.
High-precision electronic scale of the present invention, the control circuit are STM32 microcontrollers.
High-precision electronic scale of the present invention, the operating voltage of the amplifying circuit is 2.2V-5.5V.
High-precision electronic scale of the present invention, the amplifying circuit use ADA4528-2 operational amplifiers.
A kind of high-precision electronic scale of the present invention, the output voltage of the power supply is 5V.
A kind of high-precision electronic scale of the present invention, the display terminal are FTF liquid crystal displays.
A kind of high-precision electronic scale of the present invention, the button are 4 × 4 numeric keypad.
A kind of high-precision electronic scale of the present invention, the signal of collection by signal conditioning circuit handle i.e. by signal into
Row amplification is changed with A/D, is subject to data processing with reference to STM32 singlechip controllers, and is realized and inputted by outer keyboard circuit, by
FTF display screens show that low with amount of money cost, portable, intelligence of weighing is satisfied with daily demand, have to small-sized smart scale market universal
Promotional value.
Embodiment
High-precision electronic scale of the present invention, including front end signal Acquisition Circuit, amplifying circuit, power supply, digital-to-analogue conversion
Circuit, control circuit, display terminal and button；The front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit, control
Circuit is sequentially connected electrically；The control circuit is connected with display terminal；The button is connected with control circuit；The power supply
It is connected respectively with front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit and control circuit.
High-precision electronic scale of the present invention, the control circuit are STM32 microcontrollers.The work of the amplifying circuit
Voltage is 2.2V-5.5V.The amplifying circuit uses ADA4528-2 operational amplifiers.The output voltage of the power supply is 5V.Institute
It is FTF liquid crystal displays to state display terminal.The button is 4 × 4 numeric keypad.Strained using BHF350-3AA types patch type
Piece, has that price is low, the high and preferable linear characteristic of precision.There are the high-precision level of confidentiality series resistance formula foil gauges of BHF 107 circulations to make
With the average value in service life, sensitivity coefficient be separated into 0.5%., strain gauge resistance to average value tolerance be ± 0.1% the advantages that its performance
It is superior to BX Series Precision level foil gauges.Suitable for high-precision sensor and high-precision stress analysis.Resistance strain gage is pasted on
Overarm arm one end, when overarm arm is by stress-strain, the resistance value of resistance-strain on piece also changes therewith so that the electricity on resistance-strain
Pressure changes.The amplitude signal for changing voltage realizes weighing through subsequent treatment.When overarm arm does not stress, foil gauge is constant
Shape, no output voltage.Since system design measurement accuracy requires error in the range of 0~50g to be less than 0.5g, in the range of 50~500g
Error is less than 1g, and the temperature drift effect of resistance strain gage is obvious, and is easily activated the influence of the low frequency variations of voltage, we
The low noise operational amplifier of low drifting is selected, while is also contemplated that offset voltage and gain in the case of high-amplification-factor and misses
Difference overloads adc circuit front end, and the amplifier that we also require to select is rail-to-rail output performance, by comparing and surveying
Examination, this precision operational-amplifier of our final choice ADA4528-2 is as frontend amplifying circuit.ADA4528-2 is binary channels
Amplifier, has wide working power voltage scope, high-gain, the outstanding CMRR and PSRR characteristics of 2.2V to 5.5V.Offset voltage
For 2.5uV, offset voltage drift is 0.015uV/ DEG C, the application suitable for being impermissible for error source, is that accurate amplification application is preferable
Choosing.Symmetrical amplifier architecture is constituted by two drift shift amplifiers, result in formation of three transporting discharging type instrument amplifiers
The first order, good self-correction low-frequency d error, while the influence of 1/f noise is also counteracted, but to two amplifiers
Feedback resistance selection is more demanding, accomplishes to match completely as far as possible, therefore we select 1% precision resister.Select AD7791 this
ADC chips, built-in 24 sigma-delta type .ADC, wherein can be buffered containing one or without buffering Differential Input so that inside collection
Into a differential input amplifier circuit, AD7791 receives difference analogue input and differential reference voltage.To be adapted to low frequency to survey
Low-power consumption, the full simulation front end of application are measured, during using 3V power supplys, the typical power consumption of the two is 65. μ A；Using 5.V power supplys, prohibit
During with buffering, typical power consumption is 75. μ A.
Power supply is the basis of a system, and a good Power Management Design is the premise of system stable operation.The ripple of voltage
Accuracy that is dynamic, system reading will being caused to weigh.Sensor is the change voltage by pressure to the defeated of resistance strain gage
Output change, voltage it is unstable, directly result in the reliability of signal acquisition, while unstable voltage will be to amplifying electricity below
Road, AD circuits produce pressure difference imbalance, gain error and noise jamming so that system can not work.Lifted power source performance, can make be
System is more excellent.TPS7350 has perfect protection circuit, including overcurrent, overvoltage, electric voltage reverse-connection protection.It is defeated by voltage source 7.2V
Go out, be 3.3V voltages through two TPS7350 circuit conversions, be that microcontroller and display screen are powered.ADP3301-5.0 is a low noise
Sound adjuster, input service voltage range 3.V~12.V, and the load current more than 100 milliamperes is provided, there is remarkable voltage
And load regulation, only need a 0.47 μ F shunt capacitance to export when the ADP3301 is as general use.Keyboard is 4 × 4 numeral
Keyboard, in addition to simple 0 ~ 9 digital function, and by calibrating, removing the peel, monovalent, cumulative, zero, equal to replacing other keys
Function.The input of keyboard is to input to judge with state machine, and the code that STM32 control implement bodies need to perform depends on what is received
Event.So data control flow cannot be previously set, their order and selection i.e. user's stochastic inputs is made
Into event drive.
After opening initialization, signal is gathered by front end sensors, is changed by amplification, A/D, is transmitted to STM32 monolithics
Machine controller, has STM32 to carry out numerical value conversion；Judge whether external keyboard has input to respond at the same time, if nothing, STM32 will locate
The signal of reason is sent to display screen, and the weight weighed is shown by display screen；If inputted by external echo, microcontroller is according to input
Signal event, process accident；And by the data-signal of display screen display input and the result of microcontroller processing.
Claims (7)
- A kind of 1. high-precision electronic scale, it is characterised in that：Including front end signal Acquisition Circuit, amplifying circuit, power supply, digital-to-analogue conversion Circuit, control circuit, display terminal and button；The front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit, control Circuit is sequentially connected electrically；The control circuit is connected with display terminal；The button is connected with control circuit；The power supply It is connected respectively with front end signal Acquisition Circuit, amplifying circuit, D/A converting circuit and control circuit.
- 2. high-precision electronic scale according to claim 1, it is characterised in that：The control circuit is STM32 microcontrollers.
- 3. high-precision electronic scale according to claim 2, it is characterised in that：The operating voltage of the amplifying circuit is 2.2V-5.5V。
- 4. high-precision electronic scale according to claim 3, it is characterised in that：The amplifying circuit is transported using ADA4528-2 Calculate amplifier.
- A kind of 5. high-precision electronic scale according to claim 4, it is characterised in that：The output voltage of the power supply is 5V.
- A kind of 6. high-precision electronic scale according to claim 5, it is characterised in that：The display terminal is FTF liquid crystals Display screen.
- A kind of 7. high-precision electronic scale according to claim 6, it is characterised in that：The button is 4 × 4 number key Disk.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711193314.8A CN107917748A (en) | 2017-11-24 | 2017-11-24 | High-precision electronic scale |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711193314.8A CN107917748A (en) | 2017-11-24 | 2017-11-24 | High-precision electronic scale |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN107917748A true CN107917748A (en) | 2018-04-17 |
Family
ID=61897785
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711193314.8A Withdrawn CN107917748A (en) | 2017-11-24 | 2017-11-24 | High-precision electronic scale |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107917748A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109238410A (en) * | 2018-09-06 | 2019-01-18 | 芜湖职业技术学院 | A kind of high-precision electronic weighing device |
-
2017
- 2017-11-24 CN CN201711193314.8A patent/CN107917748A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109238410A (en) * | 2018-09-06 | 2019-01-18 | 芜湖职业技术学院 | A kind of high-precision electronic weighing device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20180417 |
|
| WW01 | Invention patent application withdrawn after publication |